ture hazards from hurricanes. As more information becomes available about Katrina and Rita, or as reconstruction efforts supersede planned restoration efforts reviewed as part of this study, some of the conclusions of this report may become more significant while others may become moot.
The National Research Council (NRC) recognizes that this report is being released at a time when there may be many more questions than answers. Even so, the report is provided at this difficult time in the hope that its advice on restoring and protecting coastal Louisiana can be considered as part of the nation’s strategy to rebuild the Gulf Coast and reduce the likelihood of future tragedies associated with hurricanes in the region.
Coastal wetlands develop within a fine balance of many geomorphologic and coastal ocean processes. Relative sea level rise, wave action, tidal exchange, river discharges, hurricanes and coastal storms, and the rates of sediment accretion due to sediment deposition and accumulation of organic material play particularly important roles. The interplay of these processes and the wetland’s resilience to natural or anthropogenic perturbations determine its sustainability. Some of the processes of land loss and gain in the Louisiana coastal area are natural and have occurred for centuries. Others are the result of human activities in the wetlands and the watershed of the Mississippi River system.
Annual land loss rates in coastal Louisiana have varied over the last 50 years, declining from a maximum of 100 square kilometers (km2) per yr (39 square miles [mi2] per yr) for the period 1956–1978. Cumulative loss during this 50-year period in Louisiana represents 80 percent of the coastal land loss in the entire United States. Initial efforts to prevent catastrophic land loss were implemented under the federal Coastal Wetlands Planning, Protection, and Restoration Act (CWPPRA) in partnership with Louisiana’s efforts through Act 6 (L.A.R.S. 49:213 et seq.). Passed in 1990, CWPPRA called for the development of a comprehensive Louisiana Coastal Wetlands Restoration Plan (P.L. 101-646 §303.b). The first such plan was completed in 1993 and has been in use since that time. In addition, the Louisiana Coastal Wetlands Conservation and Restoration Task Force and the Wetlands Conservation and Restoration Authority prepared a plan for the coast in 1998 entitled Coast 2050: Toward a Sustainable Coastal Louisiana (Coast 2050).
Coast 2050 was developed under a number of federal and state legislative mandates and is the result of recognition by federal, state, and local